HiLyte™ Fluor 405, SE is a new amine-reactive fluorescent dye for protein labeling. Filters designed for Alexa Fluor™ 405 dye can also be used for the HiLyte™ Fluor 405–protein conjugates. Excitation and emission wavelengths are at 407/429 nm when conjugated to macromolecules. These conjugates are suitable for immunofluorescent staining, in situ hybridization, flow cytometry and other biological applications. The AnaTag™ HiLyte™ Fluor 405 Protein Labeling Kit has all the essential components for performing the conjugation reaction and for purifying the HiLyte™ Fluor 405-protein conjugates. The entire process can take as short as half an hour. Ample materials are provided for 3 conjugation reactions with each reaction labeling up to 5 mg IgG.